On Sun, 31 Dec 2017 20:58:01 +0100, syzbot wrote: > > Hello, > > syzkaller hit the following crash on > 71ee203389f7cb1c1927eab22b95baa01405791c > git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/master > compiler: gcc (GCC) 7.1.1 20170620 > .config is attached > Raw console output is attached. > C reproducer is attached > syzkaller reproducer is attached. See https://goo.gl/kgGztJ > for information about syzkaller reproducers > > > IMPORTANT: if you fix the bug, please add the following tag to the commit: > Reported-by: syzbot+6f11c7e2a1b91d466432@xxxxxxxxxxxxxxxxxxxxxxxxx > It will help syzbot understand when the bug is fixed. See footer for > details. > If you forward the report, please keep this part and the footer. > > audit: type=1400 audit(1514740357.837:7): avc: denied { map } for > pid=3502 comm="syzkaller781065" path="/root/syzkaller781065961" > dev="sda1" ino=16481 > scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 > tcontext=unconfined_u:object_r:user_home_t:s0 tclass=file permissive=1 > WARNING: CPU: 0 PID: 3502 at sound/core/pcm_lib.c:1635 > snd_pcm_hw_param_first+0x289/0x690 sound/core/pcm_lib.c:1635 > Kernel panic - not syncing: panic_on_warn set ... > > CPU: 0 PID: 3502 Comm: syzkaller781065 Not tainted 4.15.0-rc5+ #154 > Hardware name: Google Google Compute Engine/Google Compute Engine, > BIOS Google 01/01/2011 > Call Trace: > __dump_stack lib/dump_stack.c:17 [inline] > dump_stack+0x194/0x257 lib/dump_stack.c:53 > panic+0x1e4/0x41c kernel/panic.c:183 > __warn+0x1dc/0x200 kernel/panic.c:547 > report_bug+0x211/0x2d0 lib/bug.c:184 > fixup_bug.part.11+0x37/0x80 arch/x86/kernel/traps.c:178 > fixup_bug arch/x86/kernel/traps.c:247 [inline] > do_error_trap+0x2d7/0x3e0 arch/x86/kernel/traps.c:296 > do_invalid_op+0x1b/0x20 arch/x86/kernel/traps.c:315 > invalid_op+0x22/0x40 arch/x86/entry/entry_64.S:1079 > RIP: 0010:snd_pcm_hw_param_first+0x289/0x690 sound/core/pcm_lib.c:1635 > RSP: 0018:ffff8801c013f1a0 EFLAGS: 00010293 > RAX: ffff8801c03bc3c0 RBX: ffff8801bff08dc0 RCX: ffffffff841bee19 > RDX: 0000000000000000 RSI: 00000000ffffffea RDI: ffffed0038027e28 > RBP: ffff8801c013f1f0 R08: ffffed0038027d63 R09: ffff8801c013eb10 > R10: 0000000000000001 R11: ffffed0038027d62 R12: 000000000000000d > R13: 00000000ffffffea R14: 0000000000000005 R15: 0000000000002000 > snd_pcm_hw_param_near.constprop.27+0x78d/0x9a0 sound/core/oss/pcm_oss.c:457 > snd_pcm_oss_change_params+0x17d3/0x3720 sound/core/oss/pcm_oss.c:969 > snd_pcm_oss_make_ready+0xaa/0x130 sound/core/oss/pcm_oss.c:1128 > snd_pcm_oss_sync+0x257/0x830 sound/core/oss/pcm_oss.c:1638 > snd_pcm_oss_release+0x20b/0x280 sound/core/oss/pcm_oss.c:2431 > __fput+0x327/0x7e0 fs/file_table.c:210 > ____fput+0x15/0x20 fs/file_table.c:244 > task_work_run+0x199/0x270 kernel/task_work.c:113 > exit_task_work include/linux/task_work.h:22 [inline] > do_exit+0x9bb/0x1ad0 kernel/exit.c:865 > do_group_exit+0x149/0x400 kernel/exit.c:968 > SYSC_exit_group kernel/exit.c:979 [inline] > SyS_exit_group+0x1d/0x20 kernel/exit.c:977 > do_syscall_32_irqs_on arch/x86/entry/common.c:327 [inline] > do_fast_syscall_32+0x3ee/0xf9d arch/x86/entry/common.c:389 > entry_SYSENTER_compat+0x54/0x63 arch/x86/entry/entry_64_compat.S:129 > RIP: 0023:0xf7f4ec79 > RSP: 002b:00000000ffc2c18c EFLAGS: 00000292 ORIG_RAX: 00000000000000fc > RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00000000080f0298 > RDX: 0000000000000000 RSI: 00000000080d9b78 RDI: 00000000080f02a0 > RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000000 > R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 > R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 > Dumping ftrace buffer: > (ftrace buffer empty) > Kernel Offset: disabled > Rebooting in 86400 seconds.. This must be a superfluous WARN_ON() call invoked by snd_BUG_ON() check that can be safely ignored. A quick fix patch is below. thanks, Takashi -- 8< -- From: Takashi Iwai <tiwai@xxxxxxx> Subject: [PATCH] ALSA: pcm: Remove superfluous warning syzkaller triggered kernel warnings through PCM OSS emulation at closing a stream: WARNING: CPU: 0 PID: 3502 at sound/core/pcm_lib.c:1635 snd_pcm_hw_param_first+0x289/0x690 sound/core/pcm_lib.c:1635 Call Trace: .... snd_pcm_hw_param_near.constprop.27+0x78d/0x9a0 sound/core/oss/pcm_oss.c:457 snd_pcm_oss_change_params+0x17d3/0x3720 sound/core/oss/pcm_oss.c:969 snd_pcm_oss_make_ready+0xaa/0x130 sound/core/oss/pcm_oss.c:1128 snd_pcm_oss_sync+0x257/0x830 sound/core/oss/pcm_oss.c:1638 snd_pcm_oss_release+0x20b/0x280 sound/core/oss/pcm_oss.c:2431 __fput+0x327/0x7e0 fs/file_table.c:210 .... It's a spurious snd_BUG_ON() that invokes WARN_ON(). An error returned from snd_pcm_hw_refine() shouldn't be treated as an exception, but dealt as a normal error path. There are a couple of other places using snd_BUG_ON() unnecessarily, and this patch removes these spurious snd_BUG_ON() calls. Reported-by: syzbot+6f11c7e2a1b91d466432@xxxxxxxxxxxxxxxxxxxxxxxxx Cc: <stable@xxxxxxxxxxxxxxx> Signed-off-by: Takashi Iwai <tiwai@xxxxxxx> --- sound/core/oss/pcm_oss.c | 1 - sound/core/pcm_lib.c | 4 ++-- 2 files changed, 2 insertions(+), 3 deletions(-) diff --git a/sound/core/oss/pcm_oss.c b/sound/core/oss/pcm_oss.c index e49f448ee04f..ceaa51f76591 100644 --- a/sound/core/oss/pcm_oss.c +++ b/sound/core/oss/pcm_oss.c @@ -455,7 +455,6 @@ static int snd_pcm_hw_param_near(struct snd_pcm_substream *pcm, v = snd_pcm_hw_param_last(pcm, params, var, dir); else v = snd_pcm_hw_param_first(pcm, params, var, dir); - snd_BUG_ON(v < 0); return v; } diff --git a/sound/core/pcm_lib.c b/sound/core/pcm_lib.c index 10e7ef7a8804..db7894bb028c 100644 --- a/sound/core/pcm_lib.c +++ b/sound/core/pcm_lib.c @@ -1632,7 +1632,7 @@ int snd_pcm_hw_param_first(struct snd_pcm_substream *pcm, return changed; if (params->rmask) { int err = snd_pcm_hw_refine(pcm, params); - if (snd_BUG_ON(err < 0)) + if (err < 0) return err; } return snd_pcm_hw_param_value(params, var, dir); @@ -1678,7 +1678,7 @@ int snd_pcm_hw_param_last(struct snd_pcm_substream *pcm, return changed; if (params->rmask) { int err = snd_pcm_hw_refine(pcm, params); - if (snd_BUG_ON(err < 0)) + if (err < 0) return err; } return snd_pcm_hw_param_value(params, var, dir); -- 2.15.1 _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
